How to use Codex Mini from OpenAI with API Key

Learn how to access and use Codex Mini with your OpenAI API key through TypingMind. Get started with this powerful AI model in minutes.

ChatGPT is OpenAI's conversational AI assistant now powered by the latest GPT-5 family of models released in 2025, featuring unified multimodal capabilities across text, images, and audio with advanced reasoning.

The current lineup includes GPT-5 (flagship general-purpose model with real-time routing, faster responses, reduced hallucinations, and customizable personalities), o3 (advanced reasoning model for complex math, science, and programming with 88.9% AIME accuracy), o4-mini (cost-efficient reasoning at scale with 92.7% AIME accuracy), and GPT-5-Codex (specialized for dynamic coding tasks).

Key features include autonomous tool use (web browsing, code execution, file operations), self-fact checking, multimodal unification, and variants from Nano to Pro for different use cases.

Official Documentation: https://platform.openai.com/docs/models

Codex Mini Overview

Model NameCodex Mini
ProviderOpenAI
Model IDcodex-mini-latest
Release DateMay 16, 2025
Last UpdatedMay 16, 2025
Knowledge Cutoff2024-04
Context Window200,000 tokens
Max Output100,000 tokens
Pricing /1M tokens$1.5 input
$6 output
$0.375 cache read
Input Modalitiestext
Output Modalitiestext
Capabilities
File UploadReasoningTool Calling

Complete Setup Guide

1

Get Your OpenAI API Key

First, you'll need to obtain an API key from OpenAI. This key allows you to access their AI models directly and pay only for what you use.

  1. Visit OpenAI's API console
  2. Sign up or log in to your account
  3. Navigate to the API keys section
  4. Generate a new API key (copy it immediately as some providers only show it once)
  5. Save your API key in a secure password manager or encrypted note

⚠️ Important: Keep your API key secure and never share it publicly. Store it safely as you'll need it to connect with TypingMind.

2

Configure TypingMind with OpenAI API Key

  1. Open TypingMind in your browser
  2. Click the "Settings" icon (gear symbol)
  3. Navigate to "Models" section
  4. Click "Add Custom Model"
  5. Fill in the model information:
    Name: codex-mini-latest via OpenAI (or your preferred name)
    Endpoint: https://api.openai.com/v1/chat/completions
    Model ID: codex-mini-latest
    Context Length: Enter the model's context window (e.g., 200000 for codex-mini-latest)
    OpenAI Endpoint URL input fieldcodex-mini-latesthttps://api.openai.com/v1/chat/completionscodex-mini-latest via OpenAIhttps://www.typingmind.com/model-logo.webp200000
  6. Add custom headers by clicking "Add Custom Headers" in the Advanced Settings section:
    Authorization: Bearer <OPENAI_API_KEY>:
    X-Title: typingmind.com
    HTTP-Referer: https://www.typingmind.com
  7. Enable "Support Plugins (via OpenAI Functions)" if the model supports the "functions" or "tool_calls" parameter, or enable "Support OpenAI Vision" if the model supports vision.
  8. Click "Test" to verify the configuration
  9. If you see "Nice, the endpoint is working!", click "Add Model"
3

Start chatting with Codex Mini

Now you can start chatting with Codex Mini through TypingMind:

  • Select Codex Mini from the model dropdown menu
  • Start typing your message in the chat input
  • Enjoy faster responses and better features than the official interface
  • Switch between different AI models as needed
The best frontend AI chat for codex-mini-latest via OpenRouter API KeyThe best frontend AI chat for codex-mini-latest via OpenRouter API Keycodex-mini-latestThe best frontend AI chat for codex-mini-latest via OpenRouter API Key

💡 Pro tips for better results:

Frequently Asked Questions

Do I need a subscription to use Codex Mini?

No! With OpenAI API, you pay only for what you use with no monthly subscription. Add credits to your OpenAI account and pay as you go. TypingMind is also a one-time purchase, not a subscription.

How much will it cost to use Codex Mini?

Codex Mini costs $1.5/1M input tokens and $6/1M output tokens. A typical conversation might cost $0.01-0.10 depending on length.

Can I use other models besides Codex Mini?

Yes! With OpenAI API + TypingMind, you can access all OpenAI models. Switch between them instantly in TypingMind.

Is my data private and secure?

Yes! TypingMind stores conversations locally (web version in browser, desktop version on your device). OpenAI handles API calls securely. Check OpenAI's data policy for specifics.

Can I use Codex Mini for commercial projects?

Yes! Check OpenAI's terms of service for specific commercial use policies. TypingMind supports commercial use.